The present invention relates to a stereoscopic image display apparatus and, more particularly, to a stereoscopic image display apparatus suitably used for stereoscopically displaying image information on a display device (display) such as e.g., a television, video, computer monitor, game machine, or the like, and stereoscopically observing the image information from a predetermined observation region. As conventional stereoscopic image observation methods, a method of observing parallax images based on different polarization states using, e.g., polarization spectacles, a method of guiding a predetermined one of a plurality of parallax images (viewing position images) to the eyeballs of the observer using a lenticular lens, and the like have been proposed.
In a stereoscopic image display apparatus that uses the above-mentioned polarization spectacles as the stereoscopic image observation method, parallax images from different viewing positions corresponding to the right and left eyes of the observer are displayed on a display, so that the images for the right and left eyes have different polarization states to attain stereoscopic recognition. The images for the right and left eyes are separated and observed via the polarization spectacles. At this time, as a practical method of obtaining different polarization states, a liquid crystal shutter is arranged on the display side to switch the polarization states in synchronism with the field signal of the image to be displayed on the display, and the observer who wears the polarization spectacles time-divisionally and separately observes the right and left images eye by eye, thus attaining stereoscopic viewing. However, in the stereoscopic image display apparatus using this method, the observer must always wear the polarization spectacles.
In contrast to this, in a stereoscopic image display apparatus using a lenticular lens, that allows observation of a stereoscopic image without using any polarization spectacles, since the lenticular lens is arranged in front of the display to spatially separate images for the right and left eyes of the observer, it is easy for the observer to observe a stereoscopic image.
FIG. 20 is a partial schematic sectional view showing principal part of a conventional stereoscopic image display apparatus for observing a stereoscopic image using a lenticular lens. FIG. 20 is a sectional view of principal part from the direction over the head of the observer.
In FIG. 20, reference numeral 101 denotes a liquid crystal display, which has a glass substrate, color filters, electrodes, polarization plates, backlight, and the like (not shown). Reference numeral 101a denotes a display image (display pixel portion) on the liquid crystal display. The display pixel portion 101a consists of aperture portions 102 at which color filters that form pixels are disposed, and black matrices 103 which separate adjacent pixels. A lenticular lens 104 is arranged on the surface of the liquid crystal display 101, and consists of cylindrical lenses each of which has a semi-circular section, as shown in FIG. 20, and extends in a direction perpendicular to the plane of drawing. The display pixel portion 101a of the liquid crystal display 101 is located at the focal plane of the lenticular lens 104.
As shown in FIG. 20, pairs of stripe-shaped right-hand left-eye images (R) and (L) are alternately arranged on the display pixel portion 101a in correspondence with the pitches of the lenticular lens 104, and are optically separately imaged on a right eye ER and left eye EL of the observer via the lenticular lens 104, thus realizing stereoscopic viewing.
FIG. 20 shows spatial regions where the right- and left-eye images can be respectively observed via a lenticular lens portion 104a at the central portion of the liquid crystal display 101, and as for other lenticular lens portions, right and left separated spatial regions overlap each other at the right and left eye positions of the observer, so that right and left parallax images can be evenly separately observed over the entire screen. With this method, the observation positions of the right and left parallax images alternately and repetitively appear a large number of times in the observation region.
In a stereoscopic 3D display apparatus which does not require any eyewears such as polarization eyeglasses as the one for observing a stereoscopic image, the horizontal width of each of viewing zones for the right and left eyes is nearly equal to the interval between the eyes or bigger.
In such arrangement, the right and left parallax images may reach the left and right eyes depending on the face position of the observer, and may cause so-called inverse stereoscopic viewing. For this reason, the observer can only horizontally move his or her head by a maximum of about 65 mm corresponding to the interval between the eyes.
It is an object of the present invention to provide a stereoscopic 3D display apparatus which allows the observer to satisfactorily observe a plurality of stereoscopic images from a plurality of positions by appropriately setting individual elements such as two lenticular lenses running perpendicular to each other, a mask pattern on which aperture portions and light-shielding portions are arranged at predetermined pitches, a display for dividing a plurality of parallax images into a large number of horizontal stripe-shaped parallax images and displaying the plurality of horizontal stripe-shaped parallax images at predetermined pitches in the vertical direction, and the like, upon observing a stereoscopic image using the lenticular lenses.
In order to solve the above-mentioned problems and to achieve the above object, the present invention comprises the following arrangement.
That is, an image display apparatus according to the present invention comprises: a light source device; a mask pattern which has line patterns each obtained by repetitively arranging Nxe2x88x921 or N light-shielding portions with respect to one aperture portion in a horizontal direction, and has sets each of which includes N line patterns shifted from each other in the horizontal direction by a width of the aperture portion, and which are repetitively arranged in the vertical direction; a first lenticular lens formed by arranging a plurality of cylindrical lenses, having refractive power in the horizontal direction, at a predetermined pitch in the horizontal direction; a second lenticular lens formed by arranging a plurality of cylindrical lenses, having refractive power in the vertical direction, at a predetermined pitch in the vertical direction; and a display for displaying image information, the display being illuminated by a light beam which is emitted by the light source device, transmitted through the plurality of aperture portions, and passes through the first and second lenticular lenses, and the image information having a horizontal stripe synthesized image obtained by respectively dividing N images (Nxe2x89xa73) into a plurality of horizontal stripe images, and repetitively arranging the divided horizontal stripe images in a predetermined order in correspondence with the N images at a predetermined pitch in the vertical direction.
The stereoscopic image display apparatus of the present invention allows the observer to satisfactorily observe a plurality of stereoscopic images from a plurality of positions by appropriately setting individual elements such as two lenticular lenses having running perpendicular to each other, a mask pattern on which aperture portions and light-shielding portions are arranged at predetermined pitches, a display for dividing a plurality of parallax images into a large number of horizontal stripe-shaped parallax images and displaying the plurality of horizontal stripe-shaped parallax images at predetermined pitches in the vertical direction, and the like, upon observing a stereoscopic image using the lenticular lenses.
Moreover, an image apparatus for allowing observation of image information comprises: light providing means for providing patterned light which has line unit areas each having light-existing portions and light-non-existing portions each of which is Nxe2x88x921 or N times the width of one of the light existing portions arranged alternately in a horizontal direction, and has sets each of which includes N line unit areas each of which is shifted from another one in the horizontal direction by a width of the light-existing portions, and which are repetitively arranged in the vertical direction; optical means having a plurality of first cylindrical lens functions, having refractive power in the horizontal direction, positioned to respective areas arranged at a predetermined pitch in the horizontal direction, and a plurality of second cylindrical lens functions, having refractive power in the vertical direction, positioned to respective areas arranged at a predetermined pitch in the vertical direction; display means for displaying image information, the display means being illuminated by a light which is emitted from the light-existing portions of the light providing means and effected by both of the first and second plurality of cylindrical lens functions, and the image information having a horizontal stripe synthesized image obtained by respectively dividing N images (Nxe2x89xa73) into a plurality of horizontal stripe images, and repetitively arranging the divided horizontal stripe images in a predetermined order in correspondence with the N images at a predetermined pitch in the vertical direction.
According to a preferred aspect of the present invention, the first and second lenticular lenses serve to make a light beam coming from one point of the aperture portion of the mask pattern reach a surface of the display to be converted into a collimated light beam in a horizontal section and to be substantially focused in a vertical section.
According to a preferred aspect of the present invention, the apparatus satisfies:
0.95 less than (Vd/Vm)/(L1/L2) less than 1.05
0.96 less than (Nxc3x97Vd/VL)/{(L1+L2)/2xc3x97L2} less than 1.04
0.9 less than (1/fv)/(1/L1+1/L2) less than 1.1
where VL is the vertical arrangement pitch of the plurality of cylindrical lenses of the second lenticular lens, Vd is the vertical arrangement pitch of the plurality of horizontal stripe parallax images to be displayed on the display, Vm is the vertical arrangement pitch of the plurality of line patterns of the mask pattern, L1 is the optical distance from the display to the second lenticular lens, L2 is the optical distance from the second lenticular lens to the mask pattern, and fv is the focal length of the second vertical lens in the vertical direction.
According to a preferred aspect of the present invention, the apparatus satisfies:
0.9 less than (D/Hm)/(Lh0/Lh1) less than 1.1
0.9 less than (Nxc3x97Hm/HL)/{(Lh0+Lh1)/Lh0} less than 1.1
where Lh1 is the optical distance from the first lenticular lens to the mask pattern, Lh0 is the optical distance from the first lenticular lens to a predetermined observation surface, HL is the horizontal arrangement pitch of the plurality of cylindrical lenses of the first lenticular lens, Hm is the horizontal pitch of the aperture portions of the mask pattern, and D is the separation distance between adjacent focal points of the N parallax images when light beams based on the N parallax images via the aperture portions of the mask pattern are focused on the observation surface.
According to a preferred aspect of the present invention, the N images are parallax images for N viewing positions, and the apparatus works as a stereoscopic image display to allow observer to observe stereoscopic 3D images.
According to a preferred aspect of the present invention, the numbers N and N2 of viewing positions satisfy:
0.96 less than (Vd/Vm)/(L1/L2) less than 1.05
0.96 less than {(Nxe2x88x92N2)xc3x97Vd/VL}/{(L1+L2)/2xc3x97L2} less than 1.04
0.9 less than (1/fv)/(1/L1+1/L2) less than 1.1
where N2 is the number of viewing positions, at which aperture positions on the mask pattern are set to shield light, of the number N of viewing position, VL is the vertical pitch of the second lenticular lens, Vd is the vertical pitch of a transmission type display, Vm is the vertical pitch of an emission pattern of a spontaneous type display optical element or a mask pattern having aperture and light-shielding portions arranged in a checkerboard pattern, L1 is the distance between the transmission type display and an optical system having a micropatterned structure, L2 is the distance between the optical system having the micropatterned structure, and the checkerboard-like emission pattern of the spontaneous type display optical element or the mask pattern having the aperture and light-shielding portions arranged in the checkerboard pattern, and fv is the focal length of a predetermined horizontally elongated optical unit, which makes up the optical system having the micropatterned structure, in the vertical direction.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.